Voyage of discovery: Kepler was NASA's first planet-hunting mission and it was wildly successful: so far it has discovered 2,662 exoplanets in our galaxy. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.
Kepler focused on stars thousands of light-years away and, according to NASA, showed that statistically there's at least one planet around every star in our Milky Way Galaxy.
NASA announced on Tuesday that the Kepler mission - which has transformed how we understand planets outside of our solar system - is officially over.
"Now that we know planets are everywhere, Kepler has set us on a new course that's full of promise for future generations to explore our galaxy", said Borucki.
The most recent analysis of Kepler data suggests that as many as 50 percent of visible stars have small, possibly rocky planets located within their habitable zone. TESS, the Transiting Exoplanet Survey Satellite, launched in April and is the newest planet hunter for NASA.
Kepler - which detected exoplanets by spotting the minute dips in a star's light as a planet passes before it - has experienced a number of technical issues over the years.
NASA's bigger, more powerful James Webb Space Telescope, due to launch in another few years, will then study the most promising candidates to find out whether they could support life.
As it orbits some 156 million kilometres from Earth, Keplar's radio transmitters will soon be turned off by mission engineers and the spacecraft will be left to drift forever around the sun.
It's the pioneering telescope which, for those of us on Earth, filled the galaxy with planets..
Between Kepler's original mission and the K-2 followup mission, the space telescope discovered the existence of 2,681 planets and identified many more blips around distant stars that could be planets but are still awaiting confirmation, reports The Verge.
This artist's concept obtained October 30, 2018, courtesy of NASA/Ames/JPL-Caltech/T. Pyle shows Kepler-186f, the first Earth-size planet in the habitable zone.
"We know the spacecraft's retirement isn't the end of Kepler's discoveries", Jessie Dotson, Kepler's project scientist at NASA's Ames Research Center, said in a statement. This is the first star system found to have multiple transiting planets.
Four years into the mission, after the primary mission objectives had been met, some mechanical failures temporarily halted observations. "And the Kepler mission has paved the way for future exoplanet-studying missions".
The telescope has also been used to take brightness measurements from stars, to help understand their inner workings. It began science operations in late July, as Kepler was waning, and is looking for planets orbiting 200,000 of the brightest nearby stars to Earth. As of October 29, Kepler had detected 2,681 exoplanets, with an additional 2,899 exoplanet candidates awaiting confirmation, said Jessie Dotson, Kepler project scientist at NASA Ames.
Kepler's demise was "not unexpected and this marks the end of spacecraft operations", said Paul Hertz, astrophysics division director at NASA, on a conference call with reporters.
Kepler has finally run out of fuel.
Nasa says Kepler's mission may be over but its discoveries will be studied for years to come.
Since that time, NASA changed the craft's mission to adjust to the telescope's new normal, calling the updated mission K2.